And Empire's End was written after TOTJ, the NEC was written after TOTJ. And Palp's status as strongest is certainly part of DE and remains uncontradicted. It's outright confirmed now, actually. Essential Chronology is no sourcebook and the LFL logo is right there
Fine, Leland's acknowledgment of several matters. And by the way, RPG sourcebooks? Story info goes, it's C canon according to Mr. Chee and is right on his Blog.
Firstly:
The Holocron is divided into 4 levels: G-canon, C-canon, S-canon, and N-canon.
G-canon is absolute canon; the movies (their most recent release), the scripts, the novelizations of the movies, the radio plays, and any statements by George Lucas himself. G-canon always overrides the lower levels of canon when there is a contradiction. Within G-canon, many fans follow an unofficial progression of canonicity where the movies are the highest canon, followed by the scripts, the novelizations, and then the radio plays.
C-canon is primarily comprised of elements from the Expanded Universe including books, comics, and games bearing the label of Star Wars. Games and RPG sourcebooks are a special case; the stories and general background information are themselves fully C-canon, but the other elements such as character/item statistics and gameplay are, with few exceptions, N-canon.
S-canon is "secondary" canon; the story itself is considered non-continuity, but the non-contradicting elements are still a canon part of the Star Wars universe. This includes things like the popular online roleplaying game Star Wars: Galaxies and certain elements of a few N-canon stories.
N-canon is "non-canon". What-if stories (such as stories published under the Star Wars: Infinities label), game stats, and anything else directly contradicted by higher canon ends up here. N-canon is the only level that is not considered canon by Lucasfilm.
http://forums.starwars.com/thread.jspa?threadID=152583&start=0645
Leland Acknowledging the retcon to Sith History.
"Anything in the films and from George Lucas (including unpublished internal notes that we might receive from him or from the film production department) is considered â€G†canon. Next we have what we call continuity â€C†canon which is pretty much everything else. There is secondary â€S†continuity canon which we use for some older published materials and things that may or may not fit just right. [...] Lastly there is non-continuity â€N†which we rarely use except in the case of a blatant contradiction or for things that have been cut."
"By everything else I mean EVERYthing else. Novels, comics, junior novels, videogames, trading card games, roleplaying games, toys, websites, television."»
http://www.st-v-sw.net/STSWCanon2.html#III-Canon
See? And Ragnos is never, EVER called the strongest Sith who ever lived.
And before anyone tries: The films are the highest source of canon and overwrite literally everything else, but there's a level of precedence and retcons have occured before. Dan Wallace himself said Palp> All